The c-Myb transcription factor is highly expressed in immature hematopoietic cells and down-regulated during differentiation. To define the role of c-Myb in human hematopoietic lineage commitment, we studied the effects of its silencing during the commitment of human CD34+ Hematopoietic stem/progenitor cells. In CD34+ cells c-Myb silencing determined a cell cycle arrest in G0/G1 phase which strongly decreased the clonogenic efficiency, togheter with a reduction of erythroid colonies coupled with an increase of the macrophage and megakaryocyte ones. Moreover, morphological and flow cytometry data supported the preferential macrophage and megakaryocyte differentiation of c-Myb-silenced CD34+ cells. Taken together our data indicate that c-Myb is essential for the commitment along the erythroid and granulocyte lineages but not for the macrophage and megakaryocyte differentiation. Gene expression profiling of c-Myb-silenced CD34+ cells identified some potential c-Myb targets which can account for these effects, to study by Chromatin Immunoprecipitation and Luciferase Reporter Assay.
c-myb supports erythropoiesis through the transactivation of KLF1 and LMO2 expression.
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View SamplesThe c-Myb transcription factor is highly expressed in immature hematopoietic cells and down-regulated during differentiation. To define the role of c-Myb during the terminal differentiation of hematopoietic precursors, we studied the effects of its silencing in human primary CD14-myeloblasts, which maintain a granulo-monocyte differentiation bipotentiality. c-Myb-silenced myeloblasts were blocked in the G1 phase of the cell cycle at 24 hours post-nucleofection and subsequently were forced towards macrophage differentiation, as demonstrated by immunophenotypic and morphological analysis. Indeed, c-Myb-silenced CD14- cells differentiate to macrophage even after the treatment with ATRA 10-6 M, demonstrating that the c-Myb knockdown strongly impairs the ability of myeloblasts to differentiate to granulocytes. Gene expression profiling of c-Myb-silenced CD14- cells identified some potential c-Myb targets that can account for these effects.
c-myb supports erythropoiesis through the transactivation of KLF1 and LMO2 expression.
Specimen part, Time
View SamplesHuman lymphoblastoid cell lines (EBV-immortalised B cells, LcL) obtained from subjects of different age (young 28-40 years, centenarians >95 years) were analysed for gene expression at basal culture conditions and after 48 hours of serum starvation. Lymphoid B cells from centenarians were more resistant to apoptosis induction and displayed a more developed lysosomal compartment, the most critical component of phagic machinery. In addition, cells from centenarians were capable of engulfing and digesting other cells, i.e. their siblings (even entire cells). This behavior was improved by nutrient deprivation, but strikingly, it was unaffected by the autophagy-modulating drugs rapamycin, an autophagy inducer, and 3-methyladenine, an autophagy inhibitor.
Survival features of EBV-stabilized cells from centenarians: morpho-functional and transcriptomic analyses.
Sex, Age, Specimen part, Subject
View SamplesA widely shared view reads that 'MSCs' are ubiquitous in human connective tissues, can be defined by a common in vitro phenotype, share a skeletogenic potential as assessed by in vitro differentiation assays, and coincide with the ubiquitous 'pericytes.' Using stringent in vivo differentiation assays and transcriptome analysis, we show here that human cell populations from different anatomical sources, which would all be regarded as 'MSCs' based on these criteria and assumptions, actually differ widely in their transcriptomic signature and in vivo differentiation potential. In contrast, they share the capacity to guide the assembly of functional microvessels in vivo, regardless of their anatomical source, or in situ identity as perivascular or circulating cells. This analysis further reveals that muscle 'pericytes,' which are not spontaneously osteo-chondrogenic as previously claimed, may indeed coincide with an ectopic perivascular subset of committed myogenic cells similar to satellite cells. Cord blood-derived stromal cells, on the other hand, display the unique capacity to form cartilage in vivo spontaneously, in addition to an assayable osteogenic capacity. These data suggest the need to revise current misconceptions on the origin and function of so-called 'MSCs,' with important applicative implications. The data also support the view that rather than a uniform class of 'MSCs,' different mesoderm derivatives include distinct classes of tissue-specific committed progenitors, likely of different developmental origin.
No Identical "Mesenchymal Stem Cells" at Different Times and Sites: Human Committed Progenitors of Distinct Origin and Differentiation Potential Are Incorporated as Adventitial Cells in Microvessels.
Specimen part
View SamplesGene expression profiles of 8 samples of CD34+derived normal promyelocytes
Identification of a molecular signature for leukemic promyelocytes and their normal counterparts: Focus on DNA repair genes.
Specimen part
View SamplesNatural Killer (NK) cells are the first lymphocyte population to reconstitute early after non myelo-ablative and T cell-replete haploidentical hematopoietic stem cell transplantations (h-HSCTs) with post-transplant infusion of cyclophosphamide. The present study characterizes the transient and predominant expansion starting from the 2nd week after h-HSCT of a donor-derived unconventional subset of CD56dim/CD16neg (uCD56dim) NK cells expressing remarkable high levels of NKG2A and low levels of NKp46. Both transcription and phenotypic profiles indicated that uCD56dim NK cells are a distinct NK cell subpopulation with features of late differentiation, yet retaining proliferative capability and functional plasticity to generate conventional CD56bright/CD16pos NK cells in response to IL-15 plus IL-18. uCD56dim NK cells represent by far the largest NK cell subset detectable in the following 7 weeks after h-HSCT and they also express high levels of the activating receptors NKGD and NKp30 as well as of the lytic granules Granzyme-B and Perforin. Nonetheless, uCD56dim NK cells displayed a defective cytotoxicity that could be reversed by blocking the inhibitory receptor CD94/NKG2A. These data open new important perspectives to better understand the ontogenesis/homeostasis of human NK cells and to develop a novel immune-therapeutic approach by targeting the inhibitory NKG2A check point, thus enhancing NK cell alloreactivity early after h-HSCT.
The early expansion of anergic NKG2A<sup>pos</sup>/CD56<sup>dim</sup>/CD16<sup>neg</sup> natural killer represents a therapeutic target in haploidentical hematopoietic stem cell transplantation.
Specimen part
View SamplesThe bone marrow microenvironment is composed of heterogeneous cell populations of non-hematopoietic cells with complex phenotypes and undefined trajectories of maturation. Among them, mesenchymal cells maintain the production of stromal, bone, fat and cartilage cells. Resolving these unique cellular subsets within the bone marrow remains challenging. Here, we used single-cell RNA-sequencing of non-hematopoietic bone marrow cells to define specific subpopulations. Furthermore, by combining computational prediction of the cell state hierarchy with known expression of key transcription factors, we mapped differentiation paths to the osteocyte, chondrocyte, and adipocyte lineages. Finally, we validated our findings using lineage-specific reporter strains and targeted knockdowns. Our analysis reveals differentiation hierarchies for maturing stromal cells, determines key transcription factors along these trajectories, and provides an understanding of the complexity of the bone marrow microenvironment. Overall design: Single-cell mRNA sequencing of stromal cells from mouse bone marrow. Sample Stroma1 represents 948 final filtered single cells. Sample Stroma2 represents 1899 final filtered single cells.
Mapping Distinct Bone Marrow Niche Populations and Their Differentiation Paths.
Specimen part, Cell line, Subject
View SamplesThe primary aim of this project was to identify novel factors, in particular the cell-surface protein CD109, which regulate osteoclastogenesis. Microarray analysis was performed comparing two pre-osteoclast cell lines generated from the RAW 264.7 osteoclast cell line: one that has the capacity to fuse forming large multinucleated cells and one that does not fuse. It was found that CD109 was up-regulated by > 17-fold in the osteoclast forming cell line when compared to the cell line that does not fuse.
CD109 plays a role in osteoclastogenesis.
Specimen part, Cell line
View SamplesThe double-stranded RNA binding protein Staufen2 (Stau2) is asymmetrically localized and segregated during asymmetric cell divisions in the developing mouse cortex and promotes intermediate progenitor cell fate.
Asymmetric segregation of the double-stranded RNA binding protein Staufen2 during mammalian neural stem cell divisions promotes lineage progression.
Specimen part
View SamplesTo compare the gene expression profiles of leukemia initiation cells of SALL4B transgenic mice and their control counterparts.
A SALL4/MLL/HOXA9 pathway in murine and human myeloid leukemogenesis.
Specimen part, Disease
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